Machine for planing metal sheets



4 sheets-sheet 1 ooceocoooooonn I NV E NTO R THOMAS J'EPOME MASSE Kfm@ ATTORNEY-s- June 23, 1942.

T. ,1. MASSE MACHINE FOR PLANING METAL SHEETS Filed July 28, 1939 June 23, 1942. T. J. MASSE MACHINE FOR PLANING METAL SHEETS Filed July 28, 1939.' @Sheng-sheet 2 INVENTOR THOMAS JEROME MASSE L x 'ATTORNEYS June 23, 1942. T, 1 MASSE 2,287,187

MACHINE FOB PLANINGKMETAL SHEETS Filed July 28, 1959 4 Sheets-Sheet 3 K 70V l 0 l l'l 65d '1 l# 63 33 lNvENToR 8 7 a 86 34 35 HoM/:s Ji/aoMe-M/zssg aLBY (ma MK 402 37 ATTORNEYS June23,1942. T J MASSE zzlsr MACHINE FOR PLANING METAL SHEETS .Filed Jul-y 28, 1959 4 sheets-smet 4 INVENTQR rHo/vms JEROME MASSE F/G/' 3v ,4 Q lh C ATTORNEYS Patented June 23, 1942 TE STT raar cerros Thomas Jerome Masse, Alexandria, near Sydney, New South Wales, Australia, assignor to The Edes Manufacturing Company,

Plymouth,

Mass., a corporation of Massachusetts Application July 28, 1939, Serial.` No. 286,952 In Australia March 30, 1939 21 Claims.

This invention relates to new and useful improvements in machines for planing metal sheets, particularly sheets of zinc, copper, or other nonferrous metal such as used for photo-engraving plates, so as to produce semi-finished or nished sheets having a highly uniform thickness over their entire area. The invention relates specifically to improvements in machines ofthe type disclosed and claimed in my co-pending application, Serial No. 133,740, filed March 29, 1937, which issued as United States Patent No. 2,216,538 on October 1, 1940.

As disclosed in the said co-pending application, I have heretofore provided a new type of machine for bringing Zinc or copper sheets to a dei-mite 'thickness that is uniform throughout the entire area of the sheets. This machine, among other things, includes a massive carriage mounted for movement in a true linear path beneath the path of a fast moving cutting tool or tools, the carriage having a trued upper surface and means for holding one or more sheets thereon with the entiresurface of the sheet exposed. The cutting Ktool is preferably a diamond cutter. it is secured to a rotary head fastened on the end of a nearly vertical spindle, and means are provided for revolving the spindle at high speed so as to move the tool constantly in a true circular path overlying the carriage surface, at aspeed of at least several thousand feet p er minute. The path of the tool includes a minor circular arc which extends transversely with respect to the path of the carriage, entirely across4 the sheet or sheets thereon, and truly parallel to the surface of lthe carriage. Means are provided for traversing the carriage inits` linear path beneath the cutting path of the tool at a rate such that successive swaths of the tool, across the surface of the sheet, overlap.

These new sheet suriacing machines are used to bring metal sheets to a highly uniform thickness, within a tolerance of less thanvetenthousandths of an inch-a kind of uniformity that had` not previously beenl attainable in the commercial production of photo-engraving plates. In prolonged practicaloperation of the machines as heretofore constructed, however, obstacles have been encounteredwhich tend to interfere with the desired efiiciency of operation, among which the following are notable:

The vertical spindle of the machine, which carries the rotary head and diamond cutters, is subject to vibration, and to minimize vibration the spindle has heretofore been mounted in bearings which permit no slack or movement in axial or lateral direction during the course of a planing operation. The desired accuracy in the thickness in the planed sheets is noi'l always attainable because very small variations in temperatures are liable to cause objectionable slackness or objectionable tightness in the bearings, with the result that Vibration is transmitted to the diamond tools and the Vertical position of the diamond tools with respect to the work sheet is disturbed. Also, notwithstanding elaborate provision for lubrication, seizure of the spindle in its closely-fitted bearings is liable to occur, and the bearings tend to wear in such manner as to affect the accuracy of the product. It has been found, for instance, that after .the machine has run for several hours with satisfactory results it may cease to do so because of slight displacement of the spindle in axial direction, such displacement changing the depth of cut, and therefore the thickness of the planed sheets, to an objectionable extent. When tolerances in the sheet thickness are limited within one thousandth of an inch and extreme uniformity in the ilatness and surface finish of the sheets is required, it has been found difficult to maintain a continuous output of products meeting these requirements.

Furthermore, since surface bearings have been used to carry the heavy axial load of the spindle and the tool head, there is risk of frictional heat being generated in the surface bearings, and ringing in those bearings occurs'notwithstand'- ing recourse to efficient lubricating systems.

Another objectionable feature of the earlier machines is that it has been necessary to stop the machine in order to return the carriage to its starting point to permit the removal of the planed sheet and the setting of another sheet on the carriage. When the machine is stopped, however, the temperature conditions affecting its operation change rapidly. The temperature changes resulting from a stop of ve minutes makes it necessary to run the machine idle for over twenty minutes in order to bring thetcmperatures up to the normal running point; otherwise, the new work sheet will be planed thicker at one end than at the other. The lost operating time of nearly half an hour is substantial, because the output of the machine per working day is substantially decreased. This diificulty obviously cannot be met by removing and resetting the diamond tools because the degree of accuracy necessary for suchk a resetting to correspond with the previous setting is not attainable, apart from the fact that a similar time loss would be occasioned in the tool resetting operation. Accuracy with respect to the previous setting is not attainable because the temperature conditions and the expansion of the parts are not constant owing to cooling down of the parts during .the setting operation. With the diamond tool set accurately to plane sheets to the desired thickness within a tolerance of one thousandth of an inch the machine must be run idle for over two hours before the days planing operations begin in order that the temperatures in the machine parts will rise to and be kept at a constant point while the machine is in operation, the room temperature throughout that time being maintained approximately constant.

Another difliculty that has been experienced with the earlier machines is attributable to the mounting of the work table or carriage on which sheet is held during the planing operation. The carriage has been mounted to slide on two rails which are part of the bed structure of the machine and are trued parallel with the same degree of care as is exercised, for instance, in the finishing of a lathe bed. The carriage slide faces are fitted to the bed rails. The machine bed, however, is necessarily of quite large area, as also is the carriage surface. for in practice engravers sheets of conventional size measure x 40 inches, and it is often desirable that the carriage surface be capable of holding two of these sheets side by side. The carriage surface must be a little larger in area than the sheet, (or two sheets) to be planed, and the rail faces are more than twice as long as the carriage. Having regard to practically unavoidable distortion in the bed and in the carriage after erection of the machine, which may be caused by aging of the metal of which they are constructed, or by temperature variations, or by mechanical imperfections in the bearings, it has been found that the carriage is likely to rock slightly if supported as heretofore on two slide tracks which do not remain perfect. The desired degree of accuracy in the thickness and surface finish of the sheets is not obtained, however, when any substantial rocking movement of the carriage occurs.

The use of these planing machines, as heretofore constructed, has been attended by further difficulty in setting the diamond cutting tool or tools so that the cutting edge will have the desired angle with respect to the surface of the sheet that is being planed.

The present invention is intended to provide improvements or refinements in the construction of the planing machines which will eliminate the above mentioned and other objectionable features that have been encountered in the practical operation of the machines. An object of the invention is to provide new and improved features of machine construction which increase the eficiency and utility of the machines described and claimed in my aforesaid (3o-pending applica tion, and to provide certain new features of machine construction which may be used to advantage in other types of metal working machines.

One feature of the present invention is that it provides planing machines of the type described which include improved means for effecting adjustments in the position of the cutting tools with respect to the carriage surface while ensuring movement-of the tools in an invariable path during planing operations after an adjustment has been made.

Another feature of the invention is that it provides a new mounting for the carriage on the machine bed, by which to avoid rocking movement or other instability of the carriage.

Another feature of the invention is that it provides a planing machine of the type described which is equipped for automatically arresting movement of the carriage at the ends of its path or stroke of movement, together with manually controlled means for bringing the carriage to rest at any desired point in its path.

Another feature of the invention resides in the provision of a new type of cutting tool holder for a metal cutting machine, and a new form and mounting of a cutting tool for a metal cutting machine.

Still another feature of the invention consists in the provision of means for moving the cutting tools vertically to and from a position in which the tools are clear of a work sheet on the carriage of the machine. This means also is made responsive to movement of the carriage, so that the cutting tools are raised above the sheet automatically when the carriage has reached the end of its stroke and are lowered to a precisely predetermined cutting position when the carriage has been returned to its starting point.

The present invention also provides novel means for protecting the operator of the machine by preventing striking of a work sheet by a cutting tool While the sheet isbeing placed on the carriage in preparation for a planing operation.

The following description sets forth details of a preferred embodiment of the invention, with reference to the accompanying drawings in which such embodiment is illustrated.

In the drawings,

Figure 1 is a plan view of the machine bed with the slide carriage thereon.

Figure 2 is a near side elevation of the machine.

Figure 3 is a detail sectional view of a manual drive-releasing device which acts on an end of a lead screw by which the carriage is driven.

Fig. 4 is an end elevation of the machine.

Figure 5 is a sectional elevation of the spindle, the tool head thereon, the spindle drive pulley, and the spindle bearings.

Figure 6 is a detail of the ball point downthrust bearing by which the spindle position is adjustable vertically to vary the depth of cut to be made by the diamond planer tools and to permit the spindle to rise to clear the tools from contact with the work sheet.

Figures 7 and 8 are miniature explanatory sketches showing in exaggerated proportions the transverse concaving of the carriage surface and the tilting of the spindle and the tool head.

Figure 9 is a partial elevation of the rear side of the machineas modified to embody safety appliances for preventing movement of the table until vacuum.y is established in the table chamber and the safety shutter has been raised.

Figures 10 and 11 are fragmentary sectional views of a slide valve which controls air exhaust from a Sylphon bellows, the bellow-.s being operatively connected to a downthrust bearing that acts on the top end of the spindle.

Figure 12 is a plan view of the sylphon and its associated parts which, together with parts shown in Figures 10 and 11, effect adjustment of the spindle top downthrust bearing.

Figure 13 is a top plan of one of the tool holder sockets which is fixed on the periphery of the 'aesmsrr rotary head carried. ont. the bottomA endof the machine. spindle Figure 14 isa side elevation ofsthetoolholder socket Ywitha tool'holder positioned therein.v

Figurei 15 :is a vertical section' along line; 5 ci' Figure 1.3..

Figures 16 toV 20. are` detail views of the tool holder, showing. its constructiomand thel form ofi a new type of' cuttingv diamond, and' the mounting of the diamond in the tool holder.

Figure 21,is a perspective view of the diamond cutting: tool.

Figure 22: is .an detail.: view of a; portion of' the safety locking device included in the assembly shown. in Figure 9;

AsY illustrated in the.. drawings, the machine provided: by the present: invention. employs; the samev general 1 combinations and arrangements: as disclosed in my co-pending application; Serial No. 133,740. A horizontal work table or; carriage |30 is provided for movement ini ai' xed linear path Yona massive supporting bed 30. The carriage has a truedf upper surface thereonand is equipped with means for holding a sheet or sheets on this surface with thev upper facei of the sheet entirely exposed. The; carriage. is adapted to. be moved linearly beneath; the path of one or more diamond tools which aren carried by a rotary headi 34 and are arranged.. to be moved inv a true circularpath including` aminor circular arc that'traverses'the entireA breadthv of the sheet Orsheetsheld onA the carriage. The rotary head 34 is mounted on. the end of a spindle 40, and means are providedforrevolving the spindle ati highspeed so; that ther cutting tool or tools are revolved' at; a; speedu off atleast several: thousandifeet per'minute. The tools; cut into the surfacefof the sheetsV held on; the car.- riage in arcuate swaths; of accurately predetermined1 spacing from the carriage" surface, and the carriage and the'sheets thereonare-traversed beneath the fastmoving-tools at a rate suchithat successiveswaths-of the tools overlap; The axis ofi the spindle and tool head is preferably.` tilted forwardlyY to a slight extent so that the backward swath of the tool is c1earof the sheets held on the carriage; and the surface; otl the car.- riage is concaved intransverse-direction; in conformity with the cutting pathr of the too1, it;be

ing essential that thel cutting path of they tool be truly parallel tothe carriage surface.

Referring tothe drawings for details ofi the illustrated construction; longitudinal tracks' Ill, I| and I2 are provided onthe machine: bed structure 30 and are machined' tobe truly parallel and horizontal. These tracks are illustrated as hat tracks, but theyvmay be-of' V-sectionv or inverted V-section or they may consist: of cylindrical rods xed downto the bed. A cast1ircn work table I3!) is arranged for. horizontal; movement above the bed, and a metal sheet I3, preferably of non-ferrous metal such as'brass', copper. zinc or aluminum, is fixedA down onA the face of the work table. Perforati'ons I4 extend through the sh'eet 3|) and the table topv and into the chamber I5'Y in the table body. A exible pipe-connection l-extendsfrom the chambery I5 to a vacuum pump (not shown).

As shown in Figures l. 2` andv 4, three slide shoes Il, I8 and I9 arexed to the-bottom of the table or carriage |30 and are'accurately tted to thetracks I, IIand I2. Shoe I9 is fitted to run on the middle slide I2, and it is locatednear one end of the table. Shoes and I8 are tted to run respectively on` the sldetracks I0 and II,

and they. arelocatednear theyother. endfofthe table. rlhe instability ofl the` work tablegaszghere'- tofore encountered hask been remediedby the provision of this three-pointislide bearing in the present machine; This mounting of; the work table.; eliminates allrisk of; rocking movement of the: table onthe bed.

The work. table i'sarranged to be moved-in its linear pathby means of.a.lead screw` 20 working in;a4 tapped block Zillxfwhich, is; fixed tothe table body. The. lead screwis rotatable inA endbearings` 2| and'22. fixed on the machine bed. The table might, however, be driven by hydraulic actionA with the controlvalves operated'by mechanism corresponding:functionally with; the illustrated gear box; driver arrangement, toI beY described below;

Ai grooved pulley'23 is freely rotatable adjacent one end of; thelead screw and isr V-belted to; a pulley |24 connected with a gear box. |25. The gear box is connected directly to a motor, 2'4. A manual leverA 25y is linked through a control, bar |26 to al lever armf 26; for controlling the gear box |25 to set'itt for forward; drive or'for reverse drive or ati neutral position, asthe case may be. The control bar |261` is armed with tappets |21 and |28, whichY areengaged by astrikery |29; fixed on' the` side of the-table, at end'of'stroke positions. When the striker, engages either tappet it throws-lever 26' to neutral` position and-thus automatically arrestSt-hedrive when thev table reaches either end ofA its path or' stroke; A crank 21 having a handle 23:- permits manual movement oithe table independent-ly'of-"the motor-drive, as

mayy be; required; aspring-held bolti 29 is pro,- vided' forreleasng the' crankl 2,'I` from the pulley 23 while'the gearbox is set atneutral; By manuallyv throwing the lever 25 to neutral position duringeither forward. drive or reverse drive, the table can, be brought,immediately tov rest;

The tableV surface is' straight in longitudinal direction, but' it' is concavedtransversely, asindicated in Figure'T, andthefspindleV (and the tool head which it; carries) is tiltedzforwardl'y as indicated in Figure 8, both Figure '7` and Figure 8 showing the, concavity and the tilting to an exaggerated' extent' for clarity of illustration. It is te be noted'that theconcaving of the table surface andthe tiltingof the spindle are features which are seti forth and claimed in the copending application, Serial No. 133,740, and they are therefore not claimed in themselves: as novel features` of the present application.

The table surface'on which the work sheets arecarried is machinedY in'` situ with diamond tools 38 fixed' in` the tool holders 31. Thehead carries on its periphery` two or more tool holder sockets 35 spaced symmetricallyapart, thus incidentally to obtain dynamic balance. As seen in Figures-1 andS-.twotool holder sockets are disposed diametrically opposite. The tilt in the axis of the spindle andtoolhead is justsuicient to cause the toolsto plane the table transversely while causing the tablesurfacevto be,.conc aved, for example, about fteen thousandths ofan inch. The details of the tool holder sockets, the tool holders, the diamond tool, and the setting of the diamond tools are described below with reference to FigureslB |1020 of the drawings.

The body ofv the table may be an iron casting. It is sheeted with the sheet I3 of non-ferrous metal' (preferably brass or copper) which is xed downV on it closely, for example, by screws. It is not practicable tomachine a cast iron: face satisfactorily withia diamondltoollat the cutting speed at which the machine is operated normally. The machining of the sheeted surface of the table to make it conform precisely to the path of the cutting tools should be effected by the machine itself, with diamond tools adjusted in the tool head and the machine driven at substantially the normal running speed which is used in planing rolled sheets thereon. This condition is irnportant because the table surface on which the work sheets are held during planing must correspond in contour with the swath cut which will be made on the Work sheets, thereby to ensure uniformity in the thickness of the planed Work sheets. If the machining of the table surface is effected at speeds substantially different from those used in normal operation of the machine, the surface may not be as truly parallel to the cutting path of the tool as desired during a planing operation, and the optimum accuracy in the thickness of the work sheets may not be obtained.

In some types of work the planing of the sheets is effected with a single diamond, while in other types of Work two or even four diamonds are used on the rotary head, so that a greater depth of cut may be made in a short period of time and so that at least one diamond is available to remove strain-hardened metal which may be left behind the heel of another diamond.

Upon the heavy bed 30 of the machine a bridge member 3l is straddled. This bridge member carries surface bearings for the spindle, 32 being the upper or neck bearing and 33 a shoulder bearing immediately above the tool head 34. The tool head is a circular disc of aluminum, aluminum alloy, or other light metal. It is desirable that its Weight be low in order to minimize risk of vibration. Each tool holder socket 35 is attached to the periphery of the head 34 by screw pins inserted through holes 36. A tool holder 31 may be held in each socket by a set screw 35a. An adjusting screw 35h is provided on a bracket piece 35o for lowering the Vertical position of the tool holder in its socket. A diamond cutter 38 is xed in the bottom end of each of the holders 31. The sockets 35 permit adjustment of the tool holders or stocks 31 in them about a substantially vertical axis, so as to set the cutter edges at any desired angle of contact with respect to the edge of the work sheet on the carriage or work table |30.

According to a special feature of the present invention, the tool 38 is mounted on the head 34 in a novel manner which allows any desired setting of the tool with respect to the work sheet to be effected without disturbing the mounting of the tool itself. In addition, a novel form of cutting tool and a novel mounting therefor are provided, which ensure safe and secure holding of the diamond, protect its edges against chipping and relieve it of strains such as not infrequently cause diamonds to break when mounted according to past practices.

As illustrated in Figures 16 to 20, inclusive, the stock of the tool holder 31 is reduced in diameter at its lower end and is provided with a transverse bore 31a through which extends a closely fitting rotary barrel 31h of a tool clamp device 31e. The barrel is threaded at one of its ends, and a nut 31d is provided for holding the same securely to the tool holder after it has been turned to any desired position around the axis of bore 31a. The tool clamp device includes a base member 31e integral with barrel 31h and a removable clamp member 31j. A tool cavity 31g is formed in the base member to receivev the cutting diamond. A guide element 31hl extends between members 31e and 31)c to align the latter in proper position with respect to the former, and a boss 31i is formed on the clamp member 31f in position to engage and hold a tool in the cavity 31g when the clamp member is secured to the base member by means of a clamping screw 317'.

This construction and arrangement of the tool holder 31 permits the cutting tool 38 to be clamped securely in the clamp device 31o in any convenient position which will expose its cutting edge, without regard to any particular setting of the diamond in relation to the work sheet. A precise setting of the angle between the tool face and the edge of the work sheet may be made by turning and locking the tool holder stock in its socket 35. The angle between the cutting edge of the tool and the surface of the work sheet may be adjusted precisely to any desired angle merely by turning the clamp device 31e and barrel 31h in bore 31a, whereupon nut 31d is tightened and the setting operations are complete. Thus any desired variation in the working position of the tool with respect to the work sheet may be effected Without unclamping the tool.

A further feature of this construction is that the cavity 31g is made tapered, preferably, conical in form, and the cutting diamond 38 is ground with a correspondingly shaped base 38a. The face of the diamond, as seen in Figure 19, is substantially vertical to th'e axis of rotation of the clamp device, and this face terminates in a plurality of distinct cutting edges 38h, there being four cutting edges in the illustrated form. In setting the diamond in the clamp device, a iilm of cushioning cement 39 is placed in the cavity 31g, and the conical base of the diamond is then inserted into the cavity. When the boss 311' is pressed tightly against the central portion of the diamond face by the turning of screw 317', the tapered form of the diamond and of its support, aided by the film of cushioning cement, distributes the pressure on the diamond evenly over a comparatively large supporting surface, and danger of cracking the diamond is greatly alleviated. When one cutting edge of the diamond is exposed for cutting, as seen in Figures 19 and 20, the other cutting edges are enclosed within the clamp device and are thus protected against chipping. When the exposed edge has been worn or chipped so that it is no longer useful, the diamond need not be discarded but, instead, the clamp member 31) is loosened and the diamond is turned in its cavity to expose another cutting edge.

The adjustments of the tool positions must remain undisturbed once they are accurately set in order that uniformity in the planing finish may be preserved. The tool holders having been adjusted in their mountings on the head 34, the depth of cut which the tools will make is established according to the present construction by precise adjustment of an axial thrust bearing on the top end of the spindle, as described hereinafter. In addition, the present machine is provided with ymeans permitting the spindle and diamond cutters to be raised sufficiently to clear a work sheet on the carriage, and means preferably are provided for automatically moving the cutters to and from such a raised position at the ends of the table stroke.

Above the spindle neck bearing 32 is a ball thrust bearing 4| KFigure 5) `onesraceof-.wlfiich is-xedto the spindleA and the -f other rnonerotary race of which is seated on a ring 42. The :ring 42 is integral with an upper centering cup member for an annular nest of ihelical springs 44. These springs are assembled in .compressionibetween the upper cup'member and 'a lower centering cup 43, which is supported Onupthrust framework of the main bridge 3|. `A ilockinut 4-5zis screwed on `the spindle :and bears on the top side of the inner .ball-bearingrrace, Ythis-fixing the ball vbearingand upper centering cupto'the spindle. A lock collar-46 Yholds the lower centering cup 43 in place. The whole weight of the -spindlevand .its associated parts issupported on the ball thrust bearing 4|, which reacts against the supporting framework through the cushioning springs 44. In this way the spindle is resiliently mountedand is constantly urged upwardly toward'a position in which fthe Ydiamond -tools 38 on head 34 would be Vclear of the work-sheet.

A spherical or V-cup is ,provided 1011 the top end of the spindle 40 andra hard steel 'ball 5| is seated in this cup. A cylindrical box .52 is fixed on the top side of the bridge 3|. This box is slotted through diametrically, as shown at 53, and a"filoating metal block :54 is placed in it; cross arms 55 are xed in this block, and they protrude into the slotways 53 and check the block 54so that itcannot'rotate. The block 54, however, is free for vertical movement and for lateral movement in the'box-52. A spherical cup 51 is formed inthe lower end of the block 54, tting the ball 5|. An adjusting screw 4t0, tapped through the top end of the box 52, has a spherical point 60a at its lower end which bears against the upper end of the floating blo'ck 54. VWith'this novel arrangement 'theispherical point 60a holds-the spindle assemblydownward in a constant vertical position, against the compression of springs-44, and the path ofthe tools carried by the tool head 34 may be .changed accurately 4by merely .turning .the screw i60. Since the floating block :54 fhas afreedom :for ya limited amount of Vlateral movement, it .ensures true seating of the spindle top-end and '.takes care of any lateralmovement causedbydmperfect alignment of the spindle axis with vrespect tothe sphericalpoint 50a. Thusgthe axial .adjustment ofthe spindle T40 iseiected 'by .turning of the screw 60,-the thrust :being taken on the spherical point'of the screw. The .loadof the spindle, however, is taken on `the balllbearings 4|. The upwardpressure on1the Vhard steel ball v5| is not enough to cause the degree .of friction "which would produce .heating iat this spherical point.

A lever handle 6|.is ttedion the head ofthe screw 60. This lever has a limited degree of movement between .twochecks 02 and'63 (Figure 6). lWhen the lever is ingcontact with oneiof them the spindle is raised suiciently to Vclear the diamond cutters38 fromzthe face of the work sheet. When the lever 6| is moved over into contact with ,the other .check '63 .the spindle is forced downward .1:01a ypredetermined position against the compression'of thesprings44, so that the tool is brought .down to .the .position .which it mustoccupy in order to'planezthe work sheet to a predetermined required thickness. The position ofthe check pinsGZ'and 6.3 may be changed to permit any desired setting .ofthe screw 60by means of a split vcollar 'arrangement t5, Vupon which the check pins ,aremounted vThe split collar 65 vis carried rotatably-onthe -top end of the box-52, zandsis adapted to be held in-aanyadjusted position -by a 'cl-amp vcontrolled by -the handle 65a.

VSince theneck and `shoulder bearings 321and-33 have a tendency to wear, Twhich in timewould result in slight but objectionable movement ofthe spindle 'away from a.-xed'vertical axis, these bearings are equipped with l:means 32a/and 33a, of known construct-ion, :for 4eiecting periodic tightening of them aroundthe spindle.

As shown in Figure 12, the 'lever handlehl may have a pivotal-.connectionll -to stem-|62 of ra Sylphon bellows '68 and to Van opposing-.tension V-spring '59. The ycylinder `v|58 is connected through -.apipe 1| "to -a slide valve 12 which -is connected by -a pipe 13 toia vacuum chamber. The :valve Y1-2 is operated `by the *rod y|26 (see Figure l). -At full'instroln: position of the'work table, -rod |26 vvis,pushed-forward by contactof the striker |29ontiie table, and it thusopens valve 12'to=suction, -and air is'educted from the Sylphon 68; fand-Sylphon 68 thereupon pulls'the lever arm Y=||,'turnsthescrew 60 upwards, and permits'thevspindlerll to rise, thus lifting the head34 and so raising `'thediarnond'tools clear oi the-surfaceof the'workesheet. At the end of the reverse movementof the table, air-is admitted to the Syjlphonfthrough,thevalve12,;which has now been reversed, and the -spring then acts to turn the thrust screw-*60 down land thus lower the .spindle l40 -andfsobring thediamond tools into Apredetermined cutting 1, position 4`with respect to the `surface of thework sheet. The-tool l,position istherefore brought downto planingvlevel automatically 4at the` start ofthe table forward movement, and-it is raisedautomatically at the completion of that movement.

'While thetoperator is settinganew-fwork sheet on thetablefit--wouldbepossiblefor him topush the sheet too :'far -forw-ard so 4that vit would fbe struckeby the .-tools, which fare fin movement .at high speed. To prevent thataaccident, kwhich might have Aserious consequences,.-a safety guard is provided. Thisfguard is a-downiolding Yshutter |00 which is suspended pivotally at|0| from fixed brackets ||l2 -above lthe leading 'end of ,the machine table. This shutter prevents a =work sheet vfrom being pushed past it. An arm `||l3 with lost motionis carried on the'axle |04 on which .the vshutter |00 issuspended; r.this arm |03 is connectedby a link |05 with one end offa fulcrumed lever v|0|,.and the otherendfof that lever carries a bol-1'l .|01 which `is slidable vertically in a-guide casing |08. This-bolt |01 -coacts with another bolt |09 which is normally forced down by a spring ||.0 into engagement with it. The bo1t.l09 `is carried-by :a Sylphon bellows which is fixed on one side-of themachine table and isconnected into -the vacuum chamber |5 inthe tablebody. When connection from-the vacuum lpump tothe chamber :|.5 is open to atmosphere, asis required to vpermitremoval vof a planed'she'etifromtheitable, the bolt |09 is forced down by ithespring ||0 sothat it then engages .the bolt |01. The table is then at thezfull back positionand it is checkedagainst forward motion bythese bolts. AIf bymisadventure the motor drive should-'be applied while' the table is so fchecked, a friction clutch which 'is contained in the pulley |24 slips,4 and the .table is notdri-ven. rThe lower bolt |01 vremains engaged with the v4Sylphonoperated 'bolt r |309 until anew work -sheet has'been setfdown on thetable and ivacuum "applied l'to the chamber |5fto 'hold it close down on the table surface, and until the shutter has been tilted up to the position shown in dotted lines and the bolt |01 has been thereby drawn full down out of the path of the coacting bolt |09. At the completion of the planing of a sheet and return of the table to the starting position the shutter |00 is dropped down to the full line position (see Figure 9), thus setting the bolt |01. Until both bolts |01 and |09 have been fully retired the table remains checked by them against forward movement. When a new work sheet has been placed on the table and held down thereon by vacuum in the chamber |5, operating through the perforations I4, and the shutter |00 has been raised, the table becomes automatically released for forward movement. Retirement of one of the check bolts (|01, |09) without withdrawal of the other leaves the table locked against movement, notwithstanding that the spindle remains in rotation. In practice the spindle is kept in rotation during arrests of the table movement in order -to avoid disturbance of temperature conditions in its bearings.

A hole runs through screw 50 axially and lines up with a center hole in the floating block 54; this hole is extended through the spherical cup 51, which feeds oil to the ball By introducing lubricant into screw 60 from a cup 10V, lubrication is provided to the axial thrust ball 5|, and the overilow of lubricating oil runs thence downward through the ball bearing 4| and into the bearing 32. The bearing 32 is also lubricated by vertically extending wicks which receive their oil from a cup 10V. Oil leakage from the-bottom of bearing 32 is gathered in the collar 80 and is led away through a leak pipe 8|. A shed collar |2 directs this oil drainage into the gutterway in the collar 80. The shoulder bearing 33 is wick lubricated through the cup 10X (Figure 2), and the oil which leaks down from that bearing passes out over the shed collar 85 into the gutter collar 86, whence it is turned away through the leak pipe 81. The flange X (Figure 5) on the spindle 40 immediately below the shoulder bearing 33 limits the range of upward movement of the spindle.

A screw having a spherical end may be used in substitution for the ball 5|. It is important, however, that the downward thrust of the adjusting screw on the spindle 40 be applied through a frictionless point contact, which may be either a hard steel ball or a spherical end member taking its bearing on the top end of the spindle, with provision made for a very small amount of centering movement as, for instance, by means of a member such as 54. The spindle 40 is driven, for example, by a belt extending between a pulley 58 on the spindle and a motordriven pulley 58a.

In the planing of rolled zinc sheets for engravers plates the spindle is driven at a speed which moves the diamond tools over the sheets at a speed of at least several thousand feet per minute. .A speed of about 8000 feet per minute is preferred. For zinc that speed may be substantially increased or diminished, according to the judgment of the operator. For metals other1 than zinc the speed for best operation should be determined by test on a trial sheet, and inthe case of certain metals it may be as low as 4000 feet per minute.

It will be understood that the present invention is not restricted to the details of constructionwhich are described herein for clarity of illustration, but that it extends to all equivalent CII features and constructions within the spirit of the disclosure and the scope of the appended claims.

I claim:

1. In an apparatus for machining metal including a movable work table, means for holding work to be machined on said table, a spindle rotatable in bearings above said table, a tool head fixed on one end of said spindle and at least one tool secured to said tool head, mounting means for said spindle comprising a thrust bearing and cushioning spring means on which the axial load of the spindle is supported in compression and adjustable means for applying downward pressure to the top end of the spindle in opposition to the upward thrust of said cushioning spring means.

2. In an apparatus for machining metal including a movable work table, means for holding work to be machined on said table, a spindle rotatable in bearings above said table, a tool head fixed on one end of said spindle and at least one tool secured to said tool head, mounting means for said spindle comprising a thrust bearing and cushioning spring means on which the axial load of the spindle is supported in compression and adjustable means for applying downward pressure to the top end of the spindle in opposition to the upward thrust of said cushioning spring means, said adjustable means comprising a selfcentering point bearing and means for adjusting the same in vertical direction.

3. In an apparatus for machining metal including a movable work table, means for holding work to be machined on said table, a spindle rotatable in bearings above said table, a tool head fixed on one end of said spindle and at least one tool secured to said tool head, mounting means for said spindle comprising surface bearings respectively embracing diierent portions of the tool head spindle and holding said spindle for rotation about a fixed axis, a thrust ball bearing having a rotary race secured to said spindle and a non-rotary race supported to sustain the axial thrust of said spindle and tool head, a compression spring cushion and means for transmitting the load of the spindle and tool head onto the support for said bearing through said spring cushion.

4. In an apparatus for machining metal including a movable work table, means for holding work to be machined on said table, a spindle rotatable in bearings above said table, a tool head fixed on one end of said spindle and at least one tool secured to said tool head, mounting means for said spindle comprising surface bearings respectively embracing different portions of the tool head spindle and holding said spindle for rotation about a xed axis, a thrust ball bearing having a rotary race secured to said spindle and a non-rotary race supported to sustain the axial thrust of said spindle and tool head, a compression spring cushion positioned to transmit said thrust to the support for said bearing, a spherical end thrust bearing acting on the top end of said spindle, a floating non-rotary seat for said end thrust bearing and means for applying downward pressure axially on the spindle through said seat and spherical bearing to eifect axial adjustment of the spindle by compressing said spring cushion.

5. In an apparatus for machining metal including a movable work table, means for holding work to be machined on said table, a spindle rotatable in bearings above said table, a tool head lixed on one yend of said spindle and at least one tool secured to said tool head, mounting means for said spindle comprising surface bearings respectively embracing different portions of the tool head spindle and holding said spindle for rotation about a fixed axis, a thrust ball bearing having -a rotary race secured to said spindle and a non-rotary race surrounding the spindle, a stationary support for supporting the load on said thrust bearing, an annular series of compression springs seated on said support, and means integral with said non-rotary race for resting the same on said compression springs whereby adjustably to support the load of said spindle and to'ol lhead through said compression springs.

V6. In an apparatus for machining metal including a substantial vertical spindle and means for rotating the same at high speed, mounting means for said spindle comprising surface bearing means adapted to hold said spindle for rotation about a predetermined axis, a thrust bearingand compression spring means for sustaining theaxial load of said spindle, a self-centering end thrust bearing acting on the upper end of said spindle to limit upward movement of the sameunder the infiuence of said spring means, and adjustable means for varying the vertical position of said end thrust bearing whereby to regulate the vertical position of said spindle.

'7. -In a metal sheet planing machine including a horizontal slide bed, a planing table slidable Y along said bed, means for holding a sheet of metal on the surface of said table, a nearly vertical spindle rotatable in bearings above said table, a tool head fixed on one end of said spindle and at least one cutting tool secured to said tool head, mounting means for said spindle comprising surface bearings respectively embracing different portions of the tool head spindle and holding said spindle for rotation about a fixed axis, a thrust ball bearing having a rotary race secured to said spindle 'and a non-rotary race supported to sustain the axial thrust of said spindle and tool head, a compression spring cushion, means for transmitting the load of the spindle and the tool head onto the support for said bearing through said spring cushion, a single point self-centering end thrust bearing acting on the top end of the spindle, a fioating seat for said end thrust bearing and means for applying downward pressure axially on the spindle through said seat and point to effect axial adjustment of the spindle by compressing depth of cut to be made by the tool.

8. In a metal sheet planing machine including a horizontal slide bed, a planing table slidable along said bed, means for holding a sheet of metal on the surface of said table, a nearly vertical spindle rotatable in bearings above said table, a tool head fixed on one end of said spindle and at least one cutting tool secured to said tool head, mounting means for said spindle comprising means for supporting the same under spring compression in axial direction while maintaining movement of saidcutting tool in a fixed path during a planing operation and means for changing the axial position of the spindle with respect to the carriage surface while the spindle is rotating to permit the path of the cutting tool to clear the surface of a sheet held on said table surface.

9. In a metal sheet planing machine including a horizontal slide bed, a planing table slidable along said bed, means for holding a sheet of metal on the surface of said table, a nearly Vertical spindle lrotatable in bearings above said table, a tool head fixed on one end of said spindle and at least one cutting tool secured to said tool head, mounting means for said spindle including la spring cushioned ball thrust bearing for supporting the tool head spindle resiliently in axial direction, a self-centering point on the spindle and adjustable means for applying downwardpressure `in axial direction on said point in opposition to the upward support of the spindle on said spring cushioned thrust bearing for varying the tool clearance with respect to the table on which the work-is held.

`l0. In a metal working machine including a horizontal slide bed and a massive work table slidable along said bed, a plurality of laterally spaced parallel slide tracks on said bed and three triangularlyspaced slippers fixed to the under side of said table and fitted to rest and slide on said tracks.

ll.. In a sheet metal planing machine in which the work sheet is held on a table which is traversable under a rotatable head which carries a cutting tool, a slide rail bed having three parallel slide tracks `spaced laterally apart and three slippers fixedto the under side of the table and respectively tted to run on said slide tracks, two of said slippers located ator near one end of the table and Working respectively on the outer slide tracks, and the `third slipper located at or near the other end of the table and working on the middle slide track.

12. In a metal sheet planing machine including a horizontal slide bed, a planing table slidable along said-bed, means for holding a metal sheet on the surface of said table, a nearly vertical spindle rotatable in bearings above said table, a tool head fixed on the bottom end of saidspindle and at least one cutting tool secured to Vsaid tool head, said bed comprising three trued horizontal slidevvays arranged in parallel and spaced relation and said table having three slippers mounted on the under side thereof and supported slidably en said slideways, two of said slippers being spaced apart and slidable respectively on the outer slideways and the third slipper being slidable on the middle slideway.

13. A sheet metal planing machine comprising a horizontal bed having a plurality of slideways on its top surface, a work table slidable on said slideways, said table surface being concaved transversely, means for holding a sheet to be surfaced with one face of the sheet in contact with said table surface and the other face thereof entirely exposed, means for traversing said table along said slideways under a bridge which is built on the machine bed, surface bearings in said bridge radially supporting a spindle in said bridge, a tool head fixed on the foot of said spindle and a plurality of diamond tool holders demountably fixed 0n the peripheral part of said tool head, said spindle being tilted slightly forwardly from the vertical so that the cutter swath on the work sheet is concave in correspondence with the transverse conoavity in the table surface, an axial bearing for said spindle independent of said radial bearings, said axial bearing being a thrust ball bearing, a spring cushion sustaining the spindle load on said ball bearing, and an adjustable end thrust self-centering point bearing acting downwardly on the top end of the spindle in opposition to the spring cushion support, means for applying rotation to the spindle, and means for supplying lubricating oil to said bearings.

14. In a sheet metal planing machine of the kind herein described, a downthrust self-centering point bearing at the top end of a spindle which carries a diamond tool head on its bottom end, said spindle being supported in radial surface bearings and -by an axial thrust bearing and a spring cushion resting on a common support, said downthrust point bearing comprising a hard steel ball of small diameter seated in a cup in the spindle top end, a non-rotatable pressure block movable in a fixed housing located above the spindle, a concaved contact face in the bottom end of said block accommodating said ball, and a screw tapped through the top of said housing and adapted to be rotated so as to apply downward pressure on said spindle through said block and ball in opposition to the lift applied to the spindle through said spring cushion, whereby to effect axial adjustment of said spindle in said radial surface bearings.

15. In a metal sheet planing machine including a horizontally slidable work table, means for holding a sheet to be planed on the surface of said table, a spindle rotatable in bearings above said table, a tool head fixed on the lower end of said spindle and at least one cutting tool secured to said tool head, a downward end thrust bearing for the vertical spindle in combination with a spring cushioned up-thrust bearing supporting the load of said spindle, said end thrust bearing being a ball self-centering in a cup, and an adjusting screw acting above said cup and adapted to force the spindle downward in its radial surface bearings against the lift of the spring cushion of the up-thrust bearing, whereby to adjust the clearance of the cutting tool with respect to the surface of the work table.

16. In a metal sheet planing machine including a horizontal slide bed, a planing table slidable along said bed, means for holding a sheet of metal on the surface of said table, a nearly vertical spindle rotatable in bearings above said table, a tool head xed on one end of said spindle and at least one cutting tool secured to said tool head, resilient means for urging said spindle, head and tool to a position in which the tool moves clear of a sheet on said table, adjustable means for lowering said spindle, head and tool to a cutting position in opposition to said resilient means, and means responsive to movement of said table for actuating said adjustable means whereby automatically to move said cutting tool to and from a cutting position.

17. In a metal sheet planing machine includ-V ing a horizontal slide bed, a planing table slidable along said bed, means for holding a sheet of metal on the surface of said table, a nearly vertical spindle rotatable in bearings above said table, a tool head fixed on one end of said spindle and at least one cutting tool secured to said tool head, resilient means for urging said spindle, head and tool to a position in which the tool moves clear of a sheet on said table, adjustable means for lowering said spindle, head and tool to a cutting position in opposition to said resilient means, means actuated at the end of the sliding stroke of said table for moving said adjustable means and causing the spindle to be raised by said resilient means, and means actuated when said table has been returned to starting position for moving said adjustable means and lowering said spindle to its original cutting position.

18. A metal sheet planing machine including a horizontal slide bed, a planing table slidable along said bed, driving means for sliding said table along said bed, means for holding a metal sheet on the surface of said table, a nearly vertical spindle rotatable in bearings above said table, a tool head fixed on the bottom end of said spindle and at least one cutting tool secured to said tool head, and means operated by movement of said table for rendering said driving means inoperative and arresting movement of the table at the ends of the table stroke.

19. A sheet metal planing machine including a horizontal slide bed, a planing table slidable along said bed, means for holding a sheet of metal on the surface of said table, a nearly vertical spindle rotatable in bearings above said table, a tool head fixed on one end of said spindle and at least one cutting tool secured to said tool head, means operated by movement of said table for automatically rendering said driving means inoperative and arresting movement of the table at the ends of the table stroke and manually controlled means for rendering said driving means inoperative and bringing the table to rest at any desired point in its stroke.

20. A metal sheet planing machine including a horizontal slide bed, a planing table slidable along said bed, driving means for sliding said table along said bed, means for holding a metal sheet on the surface of said table, a nearly vertical spindle rotatable in bearings above said table, a tool head xed on the bottom end of said spindle and at least one cutting tool secured to said tool head to move in a iixed cutting swath extending transverse to the path of said table and entirely across a sheet thereon, a shield' member movable between vthe path of said tool and a sheet on said table when the table is located at its starting position and means for preventing movement of the table away from its starting position when said shield member is operative.

21. A metal sheet planing machine including a horizontal slide bed, a planing table slidable along said bed, driving means for sliding said table along said bed, means for holding a metal sheet on the surface of said ta-ble, a nearly vertical spindle rotatable in bearings above said table, a tool head fixed on the bottom end of said spindle and at least one cutting tool secured to said tool head to move in a xed cutting swath extending transverse to the path of said table and entirely across a sheet thereon, a shield member movable between the path of said tool and a sheet on said table when the table is located at its starting position, and means for lpreventing movement of said table away from its starting position when either said shield member is operative or said holding means has not been made operative to hold a sheet on the table.

THOMAS J. MASSE. 

